For Flip Chip bonding, the solder bump is used commonly. In the solder bump structure, UBM (Under Bump Metallurgy), which is a multilayer of thin film interface metals, is one of the most important components to obtain reliable connections. Many studies have discussed the electromigration mechanism in lead free solder, however the mechanical properties in the high temperature range have still not been researched. When electrical current flows in the solder bump, it is heated and its temperature is raised quite significantly. In case of LED lamp that uses solder bump, the junction temperature as high as 125ºC. Thus the mechanical behavior of the solder bump material at high temperature will become increasingly important for reliability of Flip Chip bonding. We developed a micro-tensile testing system for evaluation of the mechanical properties of thin films at elevated temperatures. The testing system consists of a high temperature furnace, a motor actuator and a DIC (Digital Image Correlation) system which has 50 nm resolution and measures the strain of the specimen in real time. The testing system includes a 20N load cell whose resolution is 0.01N. Temperature range of the furnace is from room temperature to 350ºC. Programs for the testing system were written using LabVIEW 8.5 programming language and Vision Development Module 8.5. In this study, tensile tests were performed a various temperatures: room temperature, 80 ºC, 150 ºC and 210 ºC. The specimen material was electroplated thin film, which is a common solder bump material. Dog  bone shaped specimens were fabricated by MEMS (Microelectromechanical System) process. As a result, stress-strain curves were obtained for  each temperature and the mechanical properties such as Young’s modulus, yield strength and tensile strength were determined.

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/15791 must be provided.